Stroke: Assessment and Important Time Frames Outside of the Hospital

Time Frames for Acute Stroke Care

Intravenous fibrinolytic therapy is only useful if it is given within 3–4.5 hours after onset of symptoms of acute ischemic stroke.² Endovascular therapy may be pursued if it is performed within 6 hours after the onset of symptoms. Therefore, it is crucially important to elicit the exact time of symptom onset from the patient or relatives.

Recognizing the clinical signs and symptoms of acute stroke remains a challenge for the community, and studies have shown that, in most cases of stroke, the onset of symptoms occurs at home. Family members often do not recognize acute stroke symptoms even in high-risk patients (i.e., those diagnosed with atrial fibrillation or hypertension).

A proposed system of care is the Stroke Chain of Survival where the community, emergency medical services (EMS), and institutions work together to manage acute stroke.

Stroke Chain of Survival

The first link represents the recognition of stroke signs and symptoms by the patient’s family members, or the patient themself, who then call EMS. 

The second link is the immediate dispatch of EMS to the patient’s location. 

The third link is the transport of the patient to a suitable institution via EMS, with providers performing the pre arrival notification to the receiving hospital.

The fourth and final link is the diagnosis and treatment of stroke in hospital.

The 8 Ds of Stroke Care

The 8 Ds of stroke care represent diagnosis, treatment, and potential delays in stroke management³:

1. Detection – recognition of stroke symptoms
2. Dispatch – activation of EMS through public-safety access points such as 9-1-1
3. Delivery – EMS identification, management, and transport of the patient to a stroke facility
4. Door – triage to the stroke center
5. Data – rapid triage, evaluation, and management in the ED
6. Decision – neurologic consultation and therapy selection
7. Drug/Device – fibrinolytic therapy versus endovascular therapy
8. Disposition – admission to the acute stroke unit or intensive care unit

Read: Advanced Airways: Endotracheal Intubation

Stoke Assessment

The CPSS simplifies the clinical diagnosis of acute stroke for ACLS providers and is especially useful in out-of-hospital situations so that the provider can rapidly transport the patient to an appropriate stroke facility with prior notification to the ED staff.⁴

Providers use the Cincinnati Prehospital Stroke Scale to assess the patient for stroke prior to arrival at the hospital.

The CPSS includes three clinical signs that an acute stroke patient may present with: 

1. Facial droop 
2. Arm weakness 
3. Abnormal speech 

There is a 72% chance of stroke if a patient presents with one clinical sign or symptom, and an 85% chance of acute stroke if a patient demonstrates all three clinical signs and symptoms.⁵

Related Video – Hypertensive Medications For Stroke

Critical Time Periods

The NINDS set critical time periods for assessment and treatment of stroke, with fibrinolytic therapy for acute stroke patients starting as soon as possible after the patient arrives in the ED. The ideal time for treatment is within 60 minutes. 

NINDS emphasizes that the critical period for administration of fibrinolytic therapy (timed from the onset of symptoms) is 3 hours, or 4.5 hours in select patients. The administration of endovascular therapy must be administered within 6 hours from the onset of symptoms. Admission to a stroke unit or a critical care unit should be within 3 hours from when the patient enters the ED.

Critical time periods for assessment and treatment of stroke.

The Stroke Algorithm

Suspected Stroke Algorithm

The stroke algorithm is divided into several time periods for the rapid diagnosis and management of acute stroke. 

The algorithm emphasizes the duties that EMS should perform for the immediate assessment and stabilization of the patient, it demonstrates the neurologic assessment by the stroke team in a capable stroke treatment facility, and it shows the importance of a CT scan in diagnosis between ischemic and hemorrhagic stroke. 

The algorithm also stratifies the appropriateness of fibrinolytic treatment for an acute ischemic stroke patient and provides instructions for general stroke care.

Acute ischemic stroke is brought about by a significantly decreased perfusion to a portion of the brain, causing a sudden loss of function.⁶

Patients will present with signs and symptoms of stroke depending on the severity of the stroke (how and where the brain is affected). Symptoms may be intermittent or constant.

Patients will present with unilateral weakness or numbness of the face, arms, or legs. Mental confusion, slurred speech, and difficulty in understanding are clinical signs as well. Some patients may report vision loss in one or both eyes.

Patients or other people with the patient must immediately call 9-1-1 for help at the first sign of stroke. 

It is recommended that experienced EMS bring the patient to the ED. However, about one-half of patients are brought to the ED by family members, denying the patient the initial steps in management for acute stroke at the pre-hospital level and transfer with proper endorsement to a competent healthcare institution. 

Trained EMS personnel can transfer the patient to a facility that is competent in handling stroke patients. EMS personnel can also describe the patient’s situation properly to the receiving hospital. That allows the hospital to prepare for the incoming patient and provide care within the critical time period.

Critical EMS Assessments and Actions

EMS uses the CPSS to determine if the patient is experiencing symptoms of an acute stroke. Immediate transfer of an acute stroke patient to a suitable institution increases the success of their management. EMS can provide the initial steps in managing the patient while in transit. 

EMS ensures that the patient’s airway, breathing, and circulation are being managed effectively. Supplemental oxygen is provided when the O₂ saturation is less than 94%. 

EMS personnel can also check the patient’s blood glucose level during this time. That is important because hypoglycemia and hyperglycemia can sometimes be confused with stroke symptoms. 

It is important for EMS to determine when symptoms started to establish a neurologic baseline. If the patient wakes up with stroke symptoms, the neurologic baseline is assumed to be the last time the patient was seen to be normal. A family member or companion must be consulted to confirm the onset of symptoms.

EMS performs a quick history and physical examination focused on acute stroke symptoms and relays their findings to the healthcare facility of choice. That allows the receiving hospital or stroke unit to prepare to receive an acute stroke patient.

Summary

In patients experiencing acute stroke, there are established critical time frames of care and treatment that begin prior to the patient arriving at the hospital. It is essential that EMS personnel know what to look for in acute stroke and communicate appropriately with the receiving hospital or stroke unit.